Flows from Gavins Point Dam decrease, but Missouri River below Omaha continues to gain

Flows from Gavins Point Dam decrease, but Missouri River below Omaha continues to gain
The Plattsmouth Waste Water Treatment Plant has been shut down due to flood waters. (World-Herald News Service)

First, the good news for Nebraska’s waterlogged eastern shore.

With inflows from the Niobrara River upstream decreasing, the U.S. Army Corps of Engineers on Saturday continued to ratchet down releases from Gavins Point Dam near Yankton, South Dakota, which serves as the last valve on Missouri River flows along the Nebraska and Iowa border.

The Platte River at Louisville, Nebraska, was nearing its expected crest late Saturday afternoon, with estimated flows of between 170,000 and 200,000 cubic feet per second, U.S. Army Corps of Engineer and National Weather Service officials said during a conference call with state, local and tribal officials. The Platte at Louisville, however, was still well above record levels.

But the bad news was that major flooding was occurring — or forecast to occur — on the Missouri River between Nebraska City and St. Joseph, Missouri.

Significant stretches of levees from just north of the confluence of the Platte River south to near Rulo, Nebraska, had begun overtopping Saturday afternoon. Several breaches also were reported on the Missouri, including one north of Plattsmouth, another on the Iowa side of the river west of Hamburg, Iowa, and one 3 miles upstream of Brownville, Nebraska.

“I am empathetic to the challenges and loss people of the region are facing right now,” said Brig. Gen. D. Peter Helmlinger, commander of the corps’ Northwestern Division.

Additional breaches were expected over the next 24 hours, officials said Saturday evening. Peak flows in the Missouri in the Omaha area were not expected for another 24 to 48 hours.

Dams along the Papillion Creek in Omaha and Salt Creek in Lincoln, which are being inspected, were operating well Saturday evening, reducing the impact on the Platte.

On the Missouri, the corps began increasing releases from Gavins Point Dam midweek, a move officials said was necessary to evacuate runoff streaming into the reservoir above the dam. To take pressure off the reservoir, the corps shut off releases from the dam above Gavins Point.

Releases from Gavins Point were cut from 90,000 cubic feet per second Friday to 63,000 cubic feet per second Saturday evening. If all goes to plan, they’ll be scaled back to 20,000 cubic feet per second by Tuesday.

National Guard sandbags wells that supply Lincoln’s water; Omaha’s MUD says its water is safe

In a situation where normal sandbags just wouldn’t cut it, two Nebraska National Guard Black Hawk helicopters and their crews spent Saturday flying into place oversized, 1,500-pound sandbags to fortify an island on the Platte River near Ashland where three City of Lincoln wells are situated.

The wells supply some of Lincoln’s water.

The crews had flown 56 of the bags into place by noon Saturday, according to Mike Wight, a public information officer with the Nebraska Emergency Management Agency.

Donna Garden, assistant director of Lincoln Transportation and Utilities, a city agency, said in a press conference Saturday afternoon that the crews had begun work at 7 a.m. and were still working.

The Platte rose overnight Friday, reaching 24 feet by Saturday. “We’ve never seen, that we know of, it reaching that high,” Garden said. However, the river was reaching a crest by Saturday afternoon, with gauges down at North Bend and Leshara.

The island is home to three of the 44 wells that supply Lincoln’s water. All three were without power Saturday afternoon, Garden said, but power was expected to be restored soon to two of them. Another well on the bank of the river also had lost power and was expected to be restored soon. The oversized sandbags, which crews were filling near the well field, measure 4 feet square.

Meantime, Lincoln officials have been assuring residents that their water is safe.

Garden said 40 vertical wells still are operating and reservoirs are full.

The city’s water is pumped out of the ground, and not from the river itself, and is not at risk of contamination from floodwaters, the city said. Treatment plants are secure and working as designed and the system is monitored constantly.

“Lincoln is fortunate at this time to have safe drinking water,” she said.

In the Omaha area, the Metropolitan Utilities District, which provides water to much of the metropolitan area, said it was monitoring conditions on the Missouri and Platte Rivers as floodwaters rise and spark some concerns about contaminants.

As of Saturday, the utility said drinking water is safe. It still meets or exceeds all state and federal standards based on more than 1,000 tests a day, the utility said.